Method for packaging articles with transparent film



April 12, 1966 J. M. SCHMIED 3,245,193

METHOD FOR PACKAGING ARTICLES WITH TRANSPARENT FILM Original Filed Dec.28, 1961 2. Sheets-Sheet 1 JUSE A 4/. Sa /MED INVEN TOR.

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A7770P/VEV5 April 1966 J. M. SCHMIED 3,245,198

METHOD FOR PACKAGING ARTICLES WITH TRANSPARENT FILM Original Filed Dec.28, 1961 a Sheets-Sheet 2 JOSE p M SCA M/EO IN VEN TOR.

KENlJR/cK and STOLZY p76", 1Q BY 2 2 W United States Patent 3,245,198METHOD FOR PACKAGING ARTICLES WITH TRANSPARENT FILM Joseph M. Schmied,Millbrae, Calif., assignor to M-C-T Enterprises, Inc., Salinas, Calif.,a corporation of California Original application Dec. 28, 1961, Ser. No.162,744. Divided and this application Aug. 7, 1%4, Ser. No.

7 Claims. (Cl. 5332) This application is a division of my copendingapplication Serial No. 162,744 filed Dec. 28, 1961, for Method andApparatus for Field Wrapping Lettuce With Transparent Film.

- This invention relates to the art'of preparing goods for shipment andmore particularly to a device and method of wrapping articles.

Although the present invention will have substantial utility inpackaging both regularly and irregularly shaped objects, such as balls,ash trays, lamp bases and the like, and although the present inventionis not to be limited to the specific applications described herein, ithas been found useful in packaging of fruits and vegetables andespecially in prepackaging head lettuce in preparation for shipment.

It is known to prepare head lettuce for shipment in a refrigeratedcondition after it has been cut in the field by placing the lettuce inperforate corrugated boxes, placing the boxes in an air-tight tank andvacuum cooling the lettuce, i.e., cooling it by withdrawing most of theair from the tank. In such a case, a small portion of the moisture inthe lettuce is evaporated. This evaporation can cause the temperature ofthe lettuce to drop from field temperature to about 33 F. inapproximately thirty minutes. The lettuce so prepared is then shipped tomarket under refrigeration. Fresh produce such as lettuce, carrots,broccoli and other vegetables, have also heretofore been individuallywrapped both prior to shipment and by retailers prior to sale. This hasbeen done during the past few years, because there has been an increasing demand on the part of the consuming public to have commodities,particularly food, displayed and sold in transparent wrapping material.Commodities such as foods, including fruits and vegetables, wrapped withsuch a material, have a more attractive appearance to buyers than dosuch commodities when displayed in bulk. Notwithstanding thedesirability of transparent wraps, retailers who do a moderate amount ofbusiness cannot afford to invest a large amount of capital in thepurchase of equipment to wrap produce, particularly vegetables, prior tosale. It is desirable, therefore, that produce be wrapped prior toshipment. Heretofore, as far as I am aware, no low cost means have beenprovided to wrap produce conveniently, particularly in the field.

In the past, as aforesaid, produce has been individually packaged intransparent film both before and after shipment to market. Machines forso wrapping produce of which I am aware, are either complicated orineffective. The complicated machines are difiicult to use to fieldprepackage vegetables prior to shipment.

The present invention overcomes the above described and otherdisadvantages of the prior art by providing a method of packagingarticles for shipment such as head lettuce, either before it is placedin the usual perforate boxes and vacuum cooled or thereafter. Thismethod includes the steps of placing a section of wrapping material,such as transparent film over a slotted yieldable disc means having ahole therethrough surrounded on all sides, placing an article such ashead lettuce over the top of the film and depressing the article throughthe disc means to wrap it. The wrapping material so used mayadvantageously be a conventional one that may be heat sealed andpreferably one which may also be shrunk by heating.

In accordance with the present invention, the disc means is providedwith a hole therethrough of an uninterrupted circumference, wherebyexcess film is gathered together at a restricted area on the article.The article so wrapped is then preferably passed through an oven or heatsource to cause the film to shrink snugly around the article inaccordance with the prior art practices.

Thus, in accordance with the present invention, field produce, such ashead lettuce, may be more conveniently and economically prepackagedprior to shipment than it has been in the prior art. In such a case,wrapped produce, such as lettuce, will also better stand shipment andhandling. It Will also be further apparent that certain produce, such ascabbage, lettuce and broccoli, may be trimmed prior to packaging and asavings in shipping cost thereby effected.

The device of the present invention may be made relatively portable andthus produce may be easily and quickly prepackaged in the field after itis harvested. Freshness is also thus preserved. In addition, this deviceprovides means to gather excess film at a position on a product beingwrapped so that it may be easily and quickly heat sealed.

The film employed with the present invention may be of a conventionaltype known in the art as biaxially oriented polystyrene. The water vaportransmission rate of this film and the permeability of this film to air,oxygen and carbon dioxide are all of relatively high, as is well known.This film is thus useful when employed in wrapping produce andespecially in prepackaging lettuce. In particular, although somelimitation on the amount of oxygen permitted to contact lettuce may havesome beneficial effect in preserving it and preventing oxidation, it maybe preserved in better condition if the film employed in prepackaging isrelatively permeable to oxygen and carbon dioxide. The known relativelyhigh permeability to air and to water vapor of polystyrene film suggeststhe use thereof as wrapping or packaging material for leafy produce,such as lettuce. As stated previously, lettuce may be packaged inpolystyrene film and the film heat sealed. Due to the fact that a heatseal is seldom perfectly air tight, water vapor may be withdrawn from aheat sealed package through a seal that is not air tight. Still further,film having perforations in it is commercially available and may be usedin packaging lettuce in order that water vapor may be more rapidlywithdrawn through the perforations in a lettuce package for increasedspeed of vacuum cooling.

The above described and other advantages of the present invention willbe better understood from the following description when considered inconnection with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative FIG. 1is a top plan view of a packaging device constructed in accordance withthe present invention;

FIG. 2 is a sectional view taken on the line 22 of the device shown inFIG. 1;

FIG. 3 is an exploded perspective view of disc means shown in FIGS. 1and 2;

FIG. 4 is a top plan view of a packaging disc made in accordance withanother embodiment of the present invention;

FIG. 5 is a sectional view taken on the line 55 of the device shown inFIG. 4;

FIG. 6 is a top plan view of a packaging disc made in accordance withanother embodiment of the invention;

FIG. 7 is an exploded perspective view of the disc shown in FIG. 6; I

FIG. 8 is a side elevational view of a portion of a machine illustratinghow the device shown in FIG. 1, 2 and 3 may be employed to wrap a headof lettuce;

FIG. 9 is aside elevational view of the machine of FIG. 8 illustratinghow film folds are gathered on a head of lettuce prior to trimming thefilm; and

FIG. 10 is a side elevational view of the device shown in FIGS. 1, 2 and3 illustrating a conventional heat sealing step for prepackaging film.

In the drawing in FIG. 1, a packaging device is indicated generally at10 having a top platform 11 to which disc means generally indicated at12 are secured by fastening elements 13 as shown in both FIGS. 1 and 2.Fastening elements 13 also hold a bottom platform 14 on the bottom sideof disc means 12 in position. A complete enclosing structure includingspacers 15, side panels 16 and a bottom panel 17 support plates 11 and14. The packaging device 10 is completely symmetrical and for thisreason only the section 22 is shown in FIG. 2. Disc meanslZ is alsoagain shown in FIG. 3 including an upper disc 18 and a lower disc 19.Upper disc 18 is slotted at four places to provide quarters a, b, c andd. Disc-19 is similarly slotted to provide quarters e, f, g and h. Notewill, be taken that the slots between quarters a, b, c. and d lie at anangle of 45 from the slots between quarters e, f, g and h. The slotsbetween quarters a, b, c and d are generally indicated at 20 in FIG. 1.The slots between quarters e, f, g and h are indicated at dotted lines21 in FIG. 1.

From the foregoing, it will be appreciated that a biaxially orientedpolystyrene film or any other kind of film or wrapping material may beplaced over the top platform 11 of a size sufficient, for example, towrap a head of lettuce. A lettuce head is then depressed downwardlythrough openings indicated at 22 and 23 in platforms 11 and 14 andthrough registering holes 24 and 25 in discs 18 and 19. After thelettuce head has been placed through the openings 22 and 23, a portionof the wrapping will extend upwardly through the registering holes 24and 25 in discs 18 and 19 which may be both trimmed and heat sealed by awire 35 shown in FIG. 9 or simply heat sealed thereby. Note will betaken that the disposition of the. slots21 relative to slots 20 make itsubstantially impossible for a fold of wrapping material to becomelodged in either slots 20 or 21, the same not having been achievablewith prior art apparatus.

A strip of rubber 28 of rectangular cross section is fixed at its endsto side panels 16 as shown in FIG. 2 in order to permit a head oflettuce and a wrapping film to be depressed through disc means 12 to anappropriate position for sealing gathered folds at the top of a head.Strip 28 also lifts a partially wrapped head to an appropriate filmsealing position when most of the film and the head are positioned belowdisc means 12 internally of the device 10 so that the film sealing irondoes not touch the disc means 12.

In accordance with the foregoing, it will be noted that it is desirableto have an uninterrupted hole through disc means 12. The same may beprovided with a disc 12' shown in FIG. 4. Discs 18 and 19, as well asdisc 12 may all be made of rubber, although the specific material ofwhich these discs are made is immaterial except that they must beyieldable or resilient. The same is true of disc 12" shown in FIG. 6.

Disc 12' shown in FIG. has a thickness increasing from the centerthereof at a hole 24' therethrough to an outer edge thereof indicated at26.

A disc 12" shown inFIGS. 6 and 7 is identical to disc 18 with theexception that an elastic cord 27 is threaded through it around a hole24" through disc 12".

In FIG. 8, a portion of a machine 29 is shown including a shaft 30having a rubber cup 31 fixed to the lower end thereof to depress a headof'lettuce 32 on a square section of polystyre e fi m 33 throughopenings 24 and 25 of di c means 1.2.

FIG. 9 shows folds 34 of film 33 gathered by disc means 12 at the top oflettuce head 32 held in appropriate trimming and heat sealing positionsby strip of rubber 28, also shown in FIG. 9. Also shown in FIG. 9 is awire 35, which may be heated by passing electric current therethrough,to trim the top of folds 34. Folds 34 may then appear as indicated inFIG. 10 and may be folded over the top of lettuce head 32 and heatsealed with a conventional iron 36 as shown in- FIG. 10;

In accordance with the present invention, as in the prior art, lettuceheads may be individually wrapped. They may be wrapped before or aftervacuum cooling or shipment and in transparent films as is alsoconventional. It is to be noted especially that conventional filmshaving a relatively high known Water vapor transmission and a relativelyhigh known permeability to air and gasses, such as oxygen and carbondioxide, are especially useful when employed with the present invention.Although oxidation of lettuce may be retarded in some respects bylimiting the amount of oxygen in contact therewith, some produce andlettuce, especially-may be preserved in better condition for a longerperiod of'time if oxygen, carbon dioxide and watervapor areallowed topass through the film employed in wrapping:

lettuce. Still further, film having the properties of relatively highwater vapor transmission and airpermeability will not unduly interferewith subsequent vacuum cooling of produce wrapped therewith.

In practicing the present invention, the breathing requirement oflettuce and the water vapor and air permeability requirement of vacuumcooling both may be met by employing conventional films havingrelatively high known water vapor and gas permeabilitiessuch asbiaxially oriented polystyrene films. One such film-is sold under thetrade name Trycite, and another is sold under the trade name Polyfiex.

The water vapor transmission of Trycite is about six grams per 100square inches of film in twenty-four hours at 100 F. and at percentrelative humidity for a film .001 inch thick. A film .00125 inch thickmay be used in accordance with the present invention to prepackage headlettuce, but thethicknessof the film is not critical and smallthicknesses may be employed. The permeability of Trycite to air, oxygenand carbon dioxide in cubic centimeters of dry gas transmission per 100square inches of film in twenty-four hours at- 77 F. and at oneatmosphere of pressure are, respectively, 60, 210 and- 930 for a film.001 inch thick;

The water vapor transmission of Polyflex according to a test similar toASTM E96 described in WVTR of Oriented Polystyrene, Modern Packaging,December 1958, is about 4.4 grams per 100 square inches of film intwenty-four hours at 100 F. and at a relative humidity of percent for afilm .001 inch thick. The permeability ranges of Polyflex to air, oxygenand carbon dioxide in cubic centimeters of gas per square inches of filmin twenty-four hours at 73 F. and at one atmosphere of pressureaccording to an ASTM D-1434-58 test are, respectively, 62 to 90, 213 to300, and 790 to 926 for a film .001 inch thick.

From the foregoing, it will be appreciated that the wrapping procedureoutlined hereinbefore may be performed in the field at the very locationwhere lettuce is being cut. Lettuce so packaged may be passed throughheat tunnels to shrink the transparent film thereon as is conventional.Conventional biaxially oriented polystyrene film may be used.

Also in accordance with the present invention, the device 10 providesmeans whereby excess film may be gathered together at the area of holes25 and 26. The gathered film is then heat sealed in accordance with theprior art.

In practicing the present invention, the freshness of lettuce may bepreserved. by packaging immediately after In thepast, this has beencalled the breathing requirement of' harvesting in accordance with theprior art. The film, after it has been shrunk to a size firmly andsnugly fitting a lettuce head, prevents damage or deterioration of theouter leaves of the head.

Although no material handling equipment has been described orillustrated herein, it is to be noted that any conventional conveyorsystem may be employed to bring articles to be wrapped to the wrappingdevice of the present invention and to transport wrapped articles awaytherefrom.

It is a feature of the present invention that discs 18 and 19 areresilient and can thereby accommodate different sizes of articles to bewrapped without further adjustment.

Note will be taken that the present invention may be employed to packageproduce not only in the field, but also in packing sheds at shippingpoints, in terminals at receiving points, and in retail stores.

Although certain advantages are obtained through the use of severaldetailed steps and constructions set forth herein, according to some ofthe broad concepts of the present invention these particular steps andconstructions are not essential. For example, neither shrink film nor aheat tunnel for shrinking the film need necessarily be employed. Themethod and apparatus of the present invention is also not limited to thepackaging of head lettuce or any other object having a generallyspherical shape. For example, elongated rectangular objects or anyobject of an irregular shape may be packaged with the use of the presentinvention.

Although only a few specific embodiments of the invention have beendescribed and illustrated, many changes and modifications thereof willof course suggest themselves to those skilled in the art. The inventionis therefore not to be limited to the specific embodiments illustratedand described, the true scope thereof being defined only in the appendedclaims.

What is claimed is:

1. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of wrapping material over a deviceincluding a yieldable disc slit radially from a central location toprovide flaps; placing an article over the top of said material; pushingsaid article all the way through said disc flaps to a position such thatfolds of said wrapping material are formed adjacent said article whichextend upwardly through said disc; raising said partially wrappedarticle to a position in pressure contact with said disc; and securingsaid Wrapping material folds together.

2. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of wrapping material over a deviceincluding a yieldable disc slit radially from a central location toprovide flaps, said disc having two separate layers, the flaps of one ofsaid layers overlapping the slits in the other and vice versa; pushingsaid article all the way through said disc flaps to a position such thatfolds of said wrapping material are formed adjacent said article whichextend upwardly through said disc; raising said partially wrappedarticle to a position in pressure contact with said disc; and securingsaid wrapping material folds together.

3. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of wrapping material over a deviceincluding a yieldable disc slit radially from a central location toprovide flaps, said device also including resilient means to urge a bodyoutwardly of said disc, said disc having two separate layers, the flapsof one of said layers overlapping the slits in the other and vice versa,said device also including resilient means to urge a body outwardly ofsaid disc; pushing an article all the way through said disc flaps to aposition such that folds of said wrapping material are formed adjacentsaid article which extend upwardly through said disc; releasing pressureon said article to permit said resilient means to raise said partiallywrapped article to a position in pressure contact with said disc; andsecuring said wrapping material folds together.

4. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of a wrapping sheet over a yieldabledisc having means to form an opening therethrough, said device alsoincluding resilient means to urge a body outwardly of said disc; placingan article over the top of said material; pushing said article all theway through said disc to a position such that folds of said wrappingsheet sections are adjacent said article which extend upwardly throughsaid disc opening, said article thereby spreading said disc apart andallowing said disc to return to a nearly unstressed position surroundingthe folds of said wrapping sheet section as aforesaid; releasingpressure on said article to permitsaid resilient means to raise saidpartially wrapped article to a position in pressure contact with saiddisc; and securing said wrapping sheet section folds together.

5. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of a Wrapping sheet over a yieldabledisc having means to form an opening therethrough; placing an articleover the top of said sheet section; depressing the article through thedisc past the maximum transverse dimension thereof to cause the sheetsection to encompass the bottom and sides of the article and to causethe edges of the sheet section to extend upwardly from the top of thearticle and be held Within a relatively small area thereon by return ofsaid disc to a nearly unstressed position; moving said partially wrappedarticle backwardly into pressure contact with said disc; and securingthe said upwardly extending sheet section edges together while theyproject through said opening.

6. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of a wrapping sheet over a yieldabledisc having means to form an opening therethrough; placing an articleover the top of said sheet section; depressing the article through thedisc past the maximum transverse dimension thereof to cause the sheetsection to encompass the bottom and sides of the article and to causethe edges of the sheet section to extend upwardly from the top of thearticle and be held within a relatively small area thereon by return ofsaid disc to a nearly unstressed position; moving said partially wrappedarticle backwardly into pressure contact with said disc; and heatsealing the said upwardly extending sheet section edges together whilethey project through said opening.

7. The method of packaging articles for shipment, said method comprisingthe steps of: placing a section of a wrapping sheet over a resilientdisc having means to form an opening therethrough; placing an articleover the top of said sheet section; depressing the article through thedisc past the maximum transverse dimension of the article to cause thesheet section to encompass the bottom and sides of the article and tocause the edges of the sheet section to stand up in folds from the topof the article and be held within a relatively small area thereon byreturn of said disc to a nearly unstressed position; raising the therebypartially wrapped article to a position closer to but not back throughsaid disc; and fastening the said folds together while they projectthrough said opening.

References Cited by the Examiner UNITED STATES PATENTS 1,597,528 8/ 1926Lauenstein 53221 2,218,293 10/1940 Muller 5322l 2,43 9,164 9/1948Haslacher 99171 2,718,107 9/ 1955 Vaughan 53-227 3,134,679 5/ 1964Dreyfus 99--17l A. LOUIS MONACELL, Primary Examiner.

RAYMOND N. JONES, Examiner.

1. THE METHOD OF PACKAGING ARTICLES FOR SHIPMENT, SAID METHOD COMPRISINGTHE STEPS OF: PLACING A SECTION OF WRAPPING MATERIAL OVER A DEVICEINCLUDING A YIELDABLE DISC SLIT RADIALLY FROM A CENTRAL LOCATION TOPROVIDE FLAPS; PLACING AN ARTICLE OVER THE TOP OF SAID MATERIAL; PUSHINGSAID ARTICLE ALL THE WAY THROUGH SAID DISC FLAPS TO A POSITION SUCH THATFOLDS OF SAID WRAPPING MATERIAL ARE FORMED ADJACENT SAID ARTICLE WHICHEXTEND UPWARDLY THROUGH SAID DISC; RAISING SAID PARTIALLY WRAPPEDARTICLE TO A POSITION IN PRESSURE CONTACT WITH SAID DISC; AND SECURINGSAID WRAPPING MATERIAL FOLDS TOGETHER.